Despite record-breaking cases of whooping cough across the United States, California has managed to avoid a major outbreak, due in part to mandatory vaccination requirements for incoming seventh-grade students. At the start of last school year, there were winding lines at some clinics for the required booster vaccine, and despite education efforts, there was turmoil at some schools when hundreds of students were banned from classes until they got the required shot. The focus on schools, often a breeding ground for contagion, seems to have worked.